How To Include Files In Php With Windows Web Server Absolute Path

you know when you have a linux web server with apache, its easy to include the absolute path of a file

for example if i want to include a file called functions.php in my includes/ directory all i have to do is give the absolute path like this:

include('/var/www/html/includes/functions.php');

but how about if i have microsoft windows and i have apache installed on it

i thought i could just do it with:

include('C:/Inetpub/wwwroot/includes/functions.php');

well, that just doesn't work

the correct way to do it is this:

include("C:\\Inetpub\\wwwroot\\includes\\functions.php");